1. Field
One or more exemplary embodiments relate to a septic tank for generating methane gas, and more particularly, to a septic tank for generating methane gas, in which methane gas generated from excreta in the septic tank may be produced as an energy source.
2. Description of the Related Art
In general, toilets are provided in buildings such as office or school buildings, and excreta which is the final product of the digestion process of the human body is discharged to a septic tank via the toilets. The excreta discharged from the toilets and stored in the septic tank may be supplied to farmland of crops and used as a fertilizer for facilitating growth of the crops. However, recently, excreta is not much used as a fertilizer for farmland due to development of chemical fertilizers that greatly increase growth of crops in the short term. Moreover, due to environmental pollution, most of excreta is discarded after undergoing a predetermined process, and a rate of reusing the excreta as resources is very small.
An alternative way of using excreta as fuel besides as a fertilizer has recently been suggested. Korean Patent No. 0965184 (published on Jun. 14, 2010) discloses a sewage disposal tank having a methane gas collection function, in which methane gas generated during an excreta processing process is collected so as to use it as fuel. A typical toilet uses about 10 to 15 liters of water per each discharge to discharge excreta of a user. Such a large amount of discharged water is stored in the sewage disposal tank together with excreta of users. Accordingly, it is difficult for fermentation to take place in the excreta which is diluted with water so that methane gas is hardly generated.